@media screen and (max-width: 990px) {
    /*    抽屉按钮显示*/
    .burger {
        display: flex;
        border-radius: 3px;
        margin-right: 35px;
    }

    .burger span {
        transform-origin: center;
        border-radius: 3px;
        transition: all 0.3s ease-in-out;
    }

    .burger span.show.top {
        transform: rotate(45deg);
    }

    .burger span.show.middle {
        opacity: 0;
        transform: translateX(100px);
    }

    .burger span.show.bottom- {
        transform: rotate(-45deg) translateY(-10px) translateX(10px);
    }

    .burger span.active {
        background-color: #fff;
    }

    nav ul.menu {
        transform: translateX(100%);
        position: absolute;
        width: 75vw;
        flex-direction: column;
        top: 60px;
        right: 0;
        height: calc(100vh - 80px);
        background-color: #FFF;
        /*    主轴start对齐*/
        align-items: center;
        justify-content: start;
    }

    nav ul.menu.active {
        background-color: #303846;
    }

    nav ul.menu.show {
        transform: translateX(0);
    }

    nav ul.menu li {
        margin-top: 3vh;
    }

    nav ul.menu li a {
        color: #606770;
    }

    ul.menu li {
        opacity: 0;
    }


    /*首页背景图移动*/
    .intro-wrapper {
        background: none;
        grid-template-columns: 1fr;
        margin-bottom: 0;
        height: unset;
    }
    .intro-wrapper .intro-content{
        margin-top: 20vh;
        text-align: center;
    }
    ul.icon{
        justify-content: center;
    }
    .intro-wrapper button{
        margin: 60px auto;
    }
    .intro-wrapper img{
        width: 50vw;
        height: 50vh;
    }
    @keyframes slideIn {
        from {
            transform: translateX(20px);
            opacity: 0;
        }
        to {
            transform: translateX(0);
            opacity: 1;
        }
    }
    .side-nav{
        display: none;
    }
    section.posts .post-item{
        grid-template-columns: 1fr;
    }
    header{
        height: 10vh;
    }
    .intro-content span:first-child{
        margin-bottom: 30px;
    }

}